The objective had long since been secured but, on the touchline, Max Allegri was blazing. Arms waving, head shaking, his fury was unmistakable.

Juventus, four goals up on aggregate and heading inexorably to their date with destiny, switched off for one moment and Kylian Mbappe nipped in to score. It was little more than a consolation but, to Allegri, it seemed like the world had ended.

The Champions League is an obsession for Juventus and their pursuit of that shimmering trophy is accompanied by a pursuit of perfection.

Mandzukic wheels away in celebration after putting Juventus 3-0 ahead on aggregate in the 33rd minute

Mandzukic headed into the crowd to celebrate his opening strike with the jubilant home supporters

The Juventus players race to join Mandzukic after taking a giant step towards reaching next month's final in Cardiff

Italy centre back Leonardo Bonucci embraces Mandzukic as he comes back on to the field after celebrating with the crowd

Italian goalkeeper Gianluigi Buffon cannot hide his delight after seeing his side take the lead on Tuesday night

The Brazilian right back peels away to celebrate putting Juventus 4-0 up on aggregate in the two-legged tie

Alves celebrates in front of the crowd and is embraced by team-mates Buffon and Claudio Marchisio on Tuesday night

Kylian Mbappe sprints back to the halfway line after netting a second half consolation for Monaco

Juventus posted this image on Instagram of the players celebrating in the dressing room after the game

Mario Mandzukic puts Juventus ahead in the second leg from close range after an incisive counter-attack. CLICK HERE for more from MATCH ZONE.

Imagine Allegri's dismay, then, when what had been a faultless defensive record in the knockout stages had been ruined.

He was the only man, though, to feel anything like disappointment on this raucous night. Juventus will contest the greatest match in club football once more and for all that Allegri smouldered, this was a performance to show why they can go one step better than in 2015.

'The coach cares so much, when we do something he doesn't like he gets so angry,' said Paulo Dybala, the Juventus striker.

'This is a wonderful night for everyone. I will never forget it. But it's not over yet. We want to win the final.'

Juventus goalkeeper Buffon clatters into Monaco striker Radamel Falcao as he tries to catch a cross into the box

Mbappe reaches a loose ball and shoots under Buffon only to be flagged offside by the assistant referee

Falcao watches Mbappe's low shot come back off the foot of the post but the offside flag was raised

Monaco might be Europe's free scorers, a team that blitzes and buries opponents under bundles of goals, but this was a step too far.

They had spirit and tenacity but, having lost the first leg 2-0, the odds were effectively insurmountable in Turin.

Gianluigi Buffon, after all, had not conceded a Champions League goal since November 22 and the chances of those three sentries Leonardo Bonucci, Giorgio Chiellini and Andrea Barzagli crumbling at this defining moment were scant.

This, however, was not a throwback to days gone by when an Italian team would man the barricades for 90 minutes to protect a lead. No.

Juventus make defending an art form but their attack can rival anything in the business and they continually cut their opponents to ribbons.

Sami Khedira's evening came to an early end as he hobbled off to be replaced in the Juventus midfield

Moutinho, Silva and Falcao take time out to discuss tactics during the first half - but they could not guide Monaco through

Monaco goalkeeper Subasic reaches high with his right hand to deny Higuain in the opening period

Chiellini rises highest to clear the ball with his head in front of Monaco skipper Falcao inside the box

Juventus striker Mandzukic appeals to the referee after falling to the floor in a tense first half in Turin

Monaco star Mbappe sprints forward with the ball but is upended by Juventus full back and goalscorer Alves

Subasic gets down low to prevent Mandzukic from opening the scoring in the second leg on Tuesday night

In a spell between the 22nd and 44th minute, Juventus had eight clear chances to score and had it not been for an inspired performance from Danijel Subasic in Monaco's goal, what turned out to be a dismantling would have become a rout.

Gonzalo Higuain had a shot cleared off the line; Mario Mandzukic was thwarted, as was Claudio Marchisio; Dybala, the architect of the victory over Barcelona in the quarter-finals, could scarcely believe he fluffed his lines when sent clean through.

'We cannot let that happen again in the final,' Dybala admitted.

Ultimately, though, the misses never mattered. Mandzukic killed off any lingering hopes Monaco were clinging to when, at the second attempt, he made sure a magnificent cross from Dani Alves got the finish it deserved, stabbing his shot into the roof of the net after Subasic saved his initial header.

The Croatian striker scored at the second attempt after the Monaco goalkeeper got down low to save his initial header

Mandzukic pokes home from close range past a despairing Subasic to fire Juventus ahead in the second leg

Monaco defender Kamil Glik clears the ball off the line as the home side go close to adding to their advantage

Alves doubled Juventus' lead on the stroke of half time with a thunderous volley from just outside the area

The Brazilian right back's powerful strike sails past goalkeeper Subasic and ripples into the back of the net

Alves was superb and the creator turned scorer just before half-time when he thrashed a volley in from 25 yards after Subasic had failed to clear his lines with a punch.

Not for the first time, you questioned Barcelona's wisdom for allowing the Brazilian to leave them last summer.

Alves may collect number 30 in Rome on Sunday, with Serie A nearly in Juventus' hands, and it was perhaps inevitable in the second half their tempo dropped.

Juventus centre back Chiellini puts his foot through the ball to clear it upfield under pressure from Falcao

Monaco's Djibril Sidibe slides to the ground in an attempt to win the ball from Juve striker Higuain

Juventus defenders Bonucci and Chiellini were a defensive rock in Europe once again on Tuesday night

Mbappe became the first player to score against Juve in the knock-out stage of this year's Champions League

Monaco defender Glik appeared to stamp on Juventus striker Higuain midway through the second half

The Argentine striker writhes around in agony on the turf after the incident with the Polish defender

Higuain is calmed down by the Juventus staff on the touchline as he waits to re-enter play following the incident

Even still, it came as shock when Mbappe breached Juventus' defence for the first time in 690 minutes.

That – along with a stamp on Higuain by Monaco defender Kamil Glick which went unpunished – sent Allegri into a frenzy but, by the final whistle, he was smiling as those on the bench squirted bottles of water at him.

He will be smiling even wider if water is replaced by champagne on June 3.